Insane or Not insane. That is the question.?

My mother is nearly 50 and drinks about 4 to 5 caffinated cokes a day. She also has had major back surgey (a year ago) and is on heavy medication and has been for about 8 years (because of chronic back pain). She is unemployed and has been for 14 years, and almost never leaves the hous unless she is shopping. She sometimes shops for 8-14 hours. She doesn't have any real friends; she mainly speaks to her parents, husband, son, and me (her daughter); with the exception of speaking to neighbors for a few min. every now and then. She never accepts no as an answer, fights with her husband (my dad) all the time, and has occasionally (when angry) hit me or her son. I wonder if the medicine, coke, and being away from the "real world" has caused her to become slightly insane. This isn't an extremely pressing problem, but is very difficult to deal with. Please give honest answers and not treat this as a joke.